An agreement in principle has been reached to hold a meeting between the presidents of Azerbaijan and Armenia, the U.S. co-chair of the OSCE Minsk Group, James Warlick wrote on his Twitter page on March 24.

He said an agreement in principle was reached during the meetings of the OSCE Minsk Group co-chairs with the presidents of Azerbaijan and Armenia to hold a summit on the Nagorno-Karabakh issue.

"Agreement in principle to a summit to discuss Nagorno-Karabakh. We will seek dates," Warlick noted.

The conflict between the two South Caucasus countries began in 1988 when Armenia made territorial claims against Azerbaijan. Armenian armed forces have occupied 20 percent of Azerbaijan since 1992, including the Nagorno-Karabakh region and seven surrounding districts.

Azerbaijan and Armenia signed a ceasefire agreement in 1994. The co-chairs of the OSCE Minsk Group, Russia, France and the U.S. are currently holding peace negotiations.

Armenia has not yet implemented the U.N. Security Council's four resolutions on the liberation of the Nagorno-Karabakh and the surrounding regions.